Climate Change Chart of Hawaii Big Island, USA

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.95 °C compared with the earlier reference period. This is an unweighted mean of monthly means, not a day-weighted annual average, and it describes the aggregate rather than every month; it also refers to mean temperature, not daytime maximum temperatures. The largest monthly increase was in December, with a difference of +2.53 °C. That identifies the strongest monthly increase in the supplied comparison, not a uniform change across the year.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of -0.09 mm/day. This unweighted mean describes monthly averages collectively, not rainfall in every month, and the measure is a daily mean rather than a monthly total. Monthly differences were mixed: in August, mean daily rainfall had an increase of +2.18 mm/day, while January / November had a decrease of -1.89 mm/day. The latter is the largest monthly decrease, tied across the listed months; neither comparison implies the same direction in other months.

Changes in sunshine duration

Mean daily sunshine duration, averaged across calendar months, had a difference of +0.11 hours/day compared with the earlier period. This is an unweighted summary of monthly means, not a day-weighted annual average or a description of every month's conditions. The strongest monthly increase occurred in September, at +0.49 hours/day, whereas the largest decrease was in March, at -0.35 hours/day. These monthly differences show contrasting changes within the comparison, rather than a consistent shift throughout the year.

Changes in snowfall

Averaged across calendar months, mean daily snowfall had a difference of -0.03 mm/day. This unweighted summary of monthly means does not describe every month, and the daily measure should not be read as a monthly snowfall total. The largest monthly decrease was in March, with a difference of -0.20 mm/day; the largest increase was in April, at +0.01 mm/day. These are the most pronounced monthly differences in each direction, not evidence that snowfall changed uniformly across months.